As a sliding bearing for pivotally supporting a rotating shaft such as a crankshaft of an engine, a sliding bearing having a sliding surface in sliding contact with an outer peripheral surface of the rotating shaft and a relief portion formed along a circumferential direction on at least one axial end portion of the sliding surface and retreated outward in a radial direction from the sliding surface has been known (Patent Literature 1).
According to the sliding bearing having such a configuration, a lubricant flowing between the rotating shaft and the sliding bearing causes a disturbance or a swirl inside the relief portion, whereby heat is transferred from the sliding bearing to the lubricant, and the sliding bearing is cooled (25th column, FIGS. 3 and 5 to 8).